Micro-fluid ejecting devices such as ink jet printers continue to be improved as the technology for making the printheads continues to advance. New techniques are constantly being developed to provide low cost, highly reliable printers which approach the speed and quality of laser printers.
One area of improvement in the printers is in the print engine or printhead itself. This seemingly simple device is a microscopic marvel containing electrical circuits, fluid passageways and a variety of tiny parts assembled with precision to provide a powerful, yet versatile component of the printer. The printhead components must also cooperate with an endless variety of ink formulations to provide the desired print properties. Accordingly, it is important to match the printhead components to the ink and the duty cycle demanded by the printer. Slight variations in production quality can have a tremendous influence on the product yield and resulting printer performance.
An ink jet printhead typically includes a semiconductor chip and a nozzle plate attached to the chip. The semiconductor chip is typically made of silicon and contains various passivation layers, conductive metal layers, resistive layers, insulative layers and protective layers deposited on a device surface thereof. Individual ink ejection devices such as heater resistors are defined in the resistive layers and each ink ejection device corresponds to a nozzle hole in the nozzle plate for ejecting ink toward a print media. In one form of a printhead, the nozzle plates contain ink chambers and ink feed channels for directing ink to each of the ink ejection devices on the semiconductor chip. In a center feed design, ink is supplied to the ink channels and ink chambers from a slot which is formed as by chemically etching or grit blasting through the thickness of the semiconductor chip. An alternative ink feed design includes individual ink feed holes formed through the thickness of the semiconductor chip as by a deep reactive ion etching (DRIE) technique such as is described in U.S. Pat. No. 6,402,301 to Powers et al.
As advances are made in print quality and speed, a need arises for an increased number of ink ejection devices which are more closely spaced on the silicon chips. Decreased spacing between the ink ejection devices requires more reliable ink feed techniques for ink supply to the ink ejection devices. As the complexity of the printheads continues to increase, there is also a need for long-life printheads which can be produced in high yield while meeting more demanding manufacturing tolerances. Thus, there continues to be a need for improved manufacturing processes and techniques which provide improved printheads and printhead components.